Railway-traffic-controlling apparatus



Mar. 3. 1925. 1,528,505 B. E. OHAGAN I RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Auz. 15. 1924 a I R M v %(9 I INVENTOIR Patented Mar. 3, 1925.

UNITED stares rarest oFricE.

BERNARD E. OHAGAN OI SWISSVALE, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY -TRAFFIC-CONT ROLLING APPARATUS.

Application filed August 15, 1924. Serial No. 732,190.

To all whom it may concern:

Be it known that I. BERNARD E. OHAGAN, a citizen of the United States. residing at Swissvale. in the county of Alleghenv and State of Pennsylvania, have invented certain new and useful Improvements in Rail way-Trafiic-Controllinrr Apparatus, of which the following is a specification.

My invention relates to railway trafiic controlling apparatus, and particularly toapparatus of the type comprising track circuits.

I will describe one form of apparatus embodying'my invention, and will then point out the novel features'thereof in claims.

The accompanying; drawing is a diagrammatic view showing one form and arrangement of apparatus embodying my invention.

Referring to the drawing, the reference characters 1 and 1 designate the trackrails of a stretch of railway track. A track section AB is isolated electrically from the rest of the stretch by means of insulated joints 2, inserted in the track rails l and l This section AB is provided with a source of track circuit current here shown as a track transformer T having a secondary winding 7 connected across the rails adjacent the left hand end of the section. An impedance J is interposed between secondary 7 of transformer T and one rail 1 of the section in the usual manner. The. primary 8 of transformer T is constantly supplied with alternating! current from some suitable source such as an alternator M, over line wires 3 and 3. c

The section A-B is further provided with a track relay designated by the reference character R and comprising two windings 5 and 6. One winding 5 is constantly con nected across the rails adjacent the right hand end of the section, and the other winding 6 is supplied ith alternating current as will appear in detail hereinafter. The relay It may be of any suitable construction and is here shown as arelay of the induction motor type. Relays of this type have the characteristic of increasing the to que exerted on the movable element when the voltage applied to either winding of the relay is increased. Relays of this type also have the characteristic of varying their torque With variations in the sine of the phase angle between the currents in the two windings.

As is well known to those skilled in the art, the ballast leakage resistance of a stretch of track, that is, the resistance from rail "to rail. through ties and ballast, varies throuch wide limits depending upon weather conditions. hen the ballast is wet this leakage resistance is comparatively low, but when the ballast is dry the leakage resistance is comparatively high. It will be obvious that this leakage resistance is connected in parallel with secondary 7 of transformer T, and also in parallel with winding 5 of relay R. It follows that with a substantially constant voltaae across the primary :8 of transformer T. the voltages across the rails adjacent relav R and adjacent the point of con nection of secondary 7 will he larder Wl-litl the ballast resistance is high than when this ballast resistance is low. The voltaqe applied to winding" 5 of relay R will therefore varv in accordance with the condition of the ballast. and in the absence of any preventative means. the torque exerted by the relay will vary correspondingly.

An auxiliary transformer Qphas a primary winding 9 connected with 'the rails adjacent the point of connection of trans former T. \Vindinrr 6'of relay R is provided with a circuit which is connected across line wires 3 and 3 and this circui includes secondary 10 of transformer Q. the secondary 10 being soconnected in this circu t that the vo ta 'e appl ed to winding 6 by alternator M over line wires Sand 3 is reduced by the voltage of secondary 10 of transformer Q.

The parts are so proportioned that when the resistance of the track ballast is normal, the two windings of-thetrack relay are supplied with currents of such magnitude as to give the proper torque. If now the track ballast resistance decreases. the increased leakage through this ballast causes a decrease in the voltage applied to the rails by secondary 7, and a decrease in the voltage applied to winding 5 ofrelay R. The reduction in voltage across the rails adjacent point A however, causes a corresponding reduction in the voltage induced in secondary 10 of relay Q, and hence an increase in the voltageapplied to winding 6 of relay R by alternator M. Similarly if the resistance of the ballast increases, the voltage at winding 5 of relay R increases, but the voltage across the rails at transformer Q also increases and so reduces the voltage applied to the winding 6 of relay R by alternator M. It is therefore plain that variations in the voltage applied to winding 5 of relay R are compensated for by variations in the voltage applied to winding 6 and hence that the torque exerted by relay R is substantially constant irrespective of ballast conditions.

I have also discovered that with appa ratus embodying my invention, when the ballast resistance decreases the phase angle between the currents in the two windings and 6 of relay R increases. This feature tends to further compensate t'or variations in the resistance of the ballast and to prevent variations in the torque of the relay.

In the present disclosure I have shown and described the relay R- as an induction motor relay but it is understood that my invention is equally applicable to two element relays of other types.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the ap pended claims without departing from the spirit and scope 01 my invention.

Having thus described my invention. what I claim is:

1. In railway trafiic controlling apparatus comprising a stretch of track, a source of track circuit voltage connected across the rails of said stretch, track relay having a first winding connected across the rails of the stretch and a second winding supplied with voltage, the combination with the aforementioned instrumentalities oi means for varying the voltage applied to said second winding in accordance with variations in the voltage applied to the rails by said first source.

2. In railway tratlic controlling apparatus comprising a stretch of track. a source of track circuit voltage connected across the rails of said stretch, a track relay having a first winding connected across the rails ot the stretch and a second winding supplied with voltage, the combination with the aforementioned instrumentalities of means for varying the voltage applied to said second winding in accordance with variations in the ballast resistance between the rails of the stretch.

3. In railway trafiie controlling apparatus comprising a stretch of track, a source of voltage connected across the rails of said stretch, a track relay having a first winding connected across the rails of the stretch and a second winding supplied with voltage, the combination with the aforementioned instrumentalities of means for opposing the voltage applied to said second winding by an amount which increases as the ballast resistance between the rails increases,

l. In railway trafiic controlling apparatus comprising a stretch of track, a source of voltage connected across the rails of said stretch, a track relay having a first winding connected across the rails of the stretch and a second winding supplied with voltage, the

rent connected across the rails adjacent the other end of said stretch, a second winding on said relay, a source of current for said second winding, and a transformer con nected across the rails adjacent said other end of the section for controllingthe supply of current to said second winding.

6. In combination, a stretch of railway track, a two-element track relay having one winding connected across the rails of said stretch, means for supplying track circuit current to the rails of the stretch, a first source o1 substantially constant voltage, a second source of voltage which increases with increase in the voltage applied to the rails of the section, and means for applying to the second win-ding of said relay the difference between the voltage of said first source and the voltage of said second source.

7. In combination, a stretch of railway track, a two-element track relay having one winding connected across the rails of said stretch, a source of substantially constant alternating voltage, a first transformer having a primary winding connected with said source and having a secondary winding con nected across the rails of said stretch. a second transformer having a primary winding connected with the rails adjacent tl c point of connection 01"- the secondary of said iirsi transformer, and a circuit for the second winding oi said relay including said source. and the secondary of said second transformer in series opposition.

In testimony whereof I afiix my signature.

BERNARD E. OI-IAGAN.

IOU 

